IMPROVED FASTENER AND FASTENER TIGHTENING/LOOSENING DEVICE

Field of the Invention The present invention relates to a fastener and a fastener tightening/loosening device.

Background

Fasteners in the form of bolts are well known. A bolt can be formed of a threaded shank and an internally threaded head. In typical use, an internally threaded nut is screwed onto the shank to apply a clamping force between the nut and the head of the bolt. However, when the nut is to be tightened or loosened, there can be instances where rotation of the nut does not result in it rotating around the shank, instead it rotates the shank. This is because the shank rotates through the head. An aspect of the present invention seeks to address this problem.

One type of bolt fastener has a round head with the threaded shank projecting from it. Unlike a traditional hexagonally shaped head, a round head is not able to be engaged by a typical turning device, such as a spanner or a wrench, in order to hold or rotate the bolt. Nor is it able to engage a complementary hexagonally shaped recess in order to hold the head to prevent rotation of the bolt . These bolts rely on friction between the head and a clamped surface to stop the head from rotating during tightening/loosening of the nut.

It is not uncommon for the nut to seize on the shank after exposure to dust or the elements . If this occurs and the nut is to be removed, turning the nut often results in the

round head slipping and thus the bolt rotating, rather than remaining stationary. In these circumstances the nut cannot be removed normally. Instead the nut (or head of the bolt) is often cut away, which is undesirable. Also, sometimes during tightening, the nut does not rotate around the shank because the shank rotates with the nut . This can be due to the round head slipping because of insufficient fiction with the clamped surface. Another aspect of the present invention seeks to address these problems.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

In the claims of this application and in the description of the invention, except where the context requires otherwise due to express language or necessary implication, the words "comprise" or variations such as "comprises" or "comprising" are used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

Summary of the Invention

According to a first aspect of the present invention there is provided a fastener system comprising: a head part having an internally threaded hole extending from one side of the head part to another side of the head part;

an externally threaded shank arranged to engage with the internally threaded hole of the head part, the shank being of a length so as to present external thread for threaded engagement by a nut when the shank is wound into the head part; and, an externally threaded locking part arranged to engage with the internally threaded hole of the head part, whereby, in use, the shank and locking part are each wound into the head part so as to make contact with each other inside the hole, such that the locking part resists against further travel of the shank through the threaded hole .

According to a second aspect of the present invention there is provided a fastener comprising: a head part having an internally threaded hole extending from one side of the head part to another side of the head part; an externally threaded shank in threaded engagement with the internally threaded hole of the head part, the shank presenting external thread for threaded engagement by a nut; and an externally threaded locking part in threaded engagement with the internally threaded hole of the head part, wherein the shank and the locking part are in contact with each other inside the hole, such that the locking part resists against travel of the shank through the threaded hole .

In a preferred embodiment the shank has a first hole therein for receiving a holding/turning device when the locking part is engaged with the head part.

In a further preferred embodiment the locking part has a second hole therein for receiving a holding/turning device when the locking part is engaged with the head part .

Typically a bonding agent is disposed on the thread of the head part for bonding the head part to the shank and the locking part .

Preferably the head part has a hardness greater than the hardness of the locking part.

According to a third aspect of the present invention there is provided a bolt comprising: a head part; and a shank projecting form the head part, the shank having a first hole in a longitudinal end thereof, the first hole arranged for receiving a corresponding projection therein such that torque is transferred from the projection to the shank and vice versa.

In one embodiment the head part has a second hole axially aligned with the shaft, the second hole arranged for receiving a corresponding second projection therein such that torque is transferred from the second projection to the head and vice versa.

Preferably the head part has a hardness greater than the hardness of the shank.

Preferably the hardness of the head part is at least 300BH.

Preferably the head part has an external surface of frustoconical shape, the frustoconical shape narrowing toward the projection of the shank from the head part.

Preferably the narrowest part of the frustoconical shape is larger than the diameter of the shank. Thus the head part preferably has a planar surface substantially perpendicular to the length of the shank extending from the head part .

Preferably the first hole is hexagonal in shape. Preferably the second hole is hexagonal in shape.

According to a fourth aspect of the present invention there is provided a fastener tightening/loosening device comprising: a body; a socket drive extending from the body, the socket drive arranged for engaging a socket for turning a nut ; a shaft extending through the socket drive, the shaft arranged for engaging a hole of a shank of a bolt, such that when engaged with the shank torque is transferred between the shaft and the shank; wherein one of the socket drive and the shaft is arrange to rotate relative to the body, while the other does not rotate relative to the body.

Preferably the shaft is movable through the socket drive in a direction towards the body. Preferably the shaft is biased to return to a rest position.

In a preferred form the shaft is not rotatable relative to the body.

Preferably the shaft has a cross-section transverse to its length that is hexagonal in shape. Preferably the body has an immobile part with a hexagonal hole therethrough, through which the shaft can travel longitudinally but is restrained from rotating about its length.

According to a fifth aspect of the present invention there is provided a fastener tightening/loosening device comprising: a body; a socket extending from the body, the socket suitable for engaging a nut; a shaft extending through the socket, the shaft arranged for engaging a hole of a shank of a bolt, such that when engaged with the shank torque is transferred between the shaft and the shank; wherein one of the socket and the shaft is arrange to rotate relative to the body, while the other does not rotate relative to the body.

Detailed Description of the Preferred Embodiments

In order to provide a better understanding of the present invention, preferred embodiments will now be described in greater detail, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a schematic partial cross-sectional view of an embodiment of a fastener according to one aspect of the present invention; Figure 2 is an end view from the left-hand side of a shaft of Figure 1;

Figure 3 is an end view of a head and the shaft of the right-hand side of Figure l;

Figure 4 is a schematic side elevation of an embodiment of a fastener tightening/loosening device according to another aspect of the present invention; and,

Figure 5 is a close-up cross-sectional side view of part of the device of Figure 4 in use.

Referring to Figures 1 to 3, there is shown a fastener in the form of a bolt (10) comprised of a head (12) , a shank

(14) , and a locking means (16) . The shank (14) has opposed ends (20) and (38) and is provided with external thread (18) . The external thread (18) need not be in the middle of the shank (14) . The end (20) is remote from the head (12) and has an axially aligned hole (22) therein.

The head (12) has an internally threaded hole there through, with the thread represented by (36) . The hole passes between opposed surfaces (24) and (28) of the head. The head (12) is shaped with a frustoconical external surface (26) disposed between the surfaces (24) and (28) . In this embodiment the frustoconical shape is circular in perpendicular cross-section to its centre, however it need not be circular. The narrowest part of the frustoconical surface (26) has a diameter larger than the diameter of the internally threaded hole (and the diameter of the shank (14)). The difference in the diameters provides for annular surface (24) , which is perpendicular to the length of the shaft (14) .

The locking means (16) has an external thread similar (30) to the external thread (18) of the shank (14) . The locking means (16) has a first end (40) and a second end (32) . An axially aligned hole (34) extends inwardly from the second end (32) .

It can be seen that the shank (14) is screwed into the internally threaded hole of the head (12) . It is desirable for the shank (14) to be at least half way through the head (12) so that sufficient threaded engagement is provided between the shank (14) and the head such that when the fastener (10) is used in a joint and tension is applied to the shank (14) , the head (12) can be loaded so as to clamp the object being fastened (in order to form the joint) without there being a failure of the engagement between the shank (14) and the head (12) .

The locking means (16) is screwed into the opposite end of the head (12) so that the end (40) of the locking means (16) makes contact with the end (38) of the shank (14) . Once contact is made further rotation of the shank (14) into the head (12) is prevented since attempted movement of the shank (14) into the head (12) pushes against the locking means (16) whereupon the thread (30) of the locking means (16) grips the internal thread (36) of the head (12) resisting this movement.

Typically a bonding agent (not shown) is used to bond the inside surface of the hole through the head (12) to the locking means (16) and shank (14) , thereby further resisting movement of the shank (14) through the head

(12), but also resisting removal of the shank (14) and the locking means (16) from the head (12) . Preferably the bonding agent is an anaerobic adhesive, such as a thread locker.

The fastener (10) can be used as the bolt system described in Australian Provisional Patent Application No.

- S -

2005901394, the contents of which are incorporated herein by reference.

It will be appreciated that by forming the bolt (10) of the head (12) and the threaded shank (14) in this manner, the head (12) can have different properties to that of the shank (14) . Typically the shank (14) is formed of mild steel; however, the head (12) may be formed of a much harder material so as to be used to clamp, for example, a wear plate, which will typically have a high hardness to resist wear. Thus, in this application, the head (12) will usually have a hardness the same as the hardness of the wear plate. Typically this will be at least a hardness of 300BH, more often at least 350BH, with hardnesses also known to be of 400 - 700BH.

The holes (22 and 34) are desirably hexagonal in shape so as to receive an Allen key or similar device.

Thus, to manufacture the bolt (10) , the bonding adjacent is applied to the inside of the hole through the head (12) and/or to the end potions of the shank (14) and locking means (16) that will be located in the head (12) . The locking means (16) can then be screwed into the head (12) to a desired depth using an Allen key and the shank (14) can likewise be screwed into the head (12) so as to contact the locking means (16) , also using an Allen key or similar. The order of screwing these into the head (12) is not essential and may depend on the intended use of the fastener (10) . The locking means (16) and shank (14) can be tightened by rotating the respective Allen keys in opposite directions, thereby locking the shank (14) in position within the head (12) .

In use, the bolt (10) can be inserted within a correspondingly shaped recess of a part to be clamped, such as on the wearing side of a wear plate. On the other side of the wear plate and support structure, a nut (not shown) can then be screwed on to the threaded shank (14) . Thus, when the nut is screwed onto the shank (14) , the shank (14) is prevented from moving through the head (12) due to the locking means (16) .

In a wear plate application, it is expected the protruding portion of the locking means (16) will be quickly worn away and the remainder of the locking means (16) will be worn as the head (12) wears away.

It will be appreciated that the head need not be in the form illustrated. For example, it could be more flange- like with a flat or rounded end, or could have a standard hexagonal shape .

Referring to Figures 4 and 5, there is shown a tightening/loosening device (100) in the form of a handheld tool gun, with a standard pistol grip. The device comprises a body (102) , a socket drive (106) projecting from the body (102) and a shaft extending co-axially through the socket drive (106) into the body (102) .

The shaft (104) is linearly moveable through the socket drive and within the body (102) . At least one brace (108) , in this case two braces (108) , are fixed to the body (102) . Each brace (108) has a suitably shaped hole though which the shaft (104) can travel. The braces (108) restrict the shaft to linear movement and prevent the

shaft (104) from rotating with respect to the body (102) . Typically the shaft (104) is of a hexagonal shape in cross-section so as to operate in a similar manner to an Allen key. The holes of the braces (108) are also hexagonalIy shaped.

Preferably the internal end (118) of the shaft (104) is spaced from the rear of the body (102) so as to form a gap (110) . It is desirable for a spring (not shown) to be placed within the gap (110) in contact with end (118) so as to allow the shaft to retreat into the body (102) , but also to urge it to return to its fully extended position. The rear of the body (102) may have a hatch (112) to allow access to the shaft (104) , so that should it become damaged, it can be removed and thus replaced. The spring can be fixed to the body (102) or to the hatch (112) .

The socket drive (106) is connected to a motor (116) via gears (114) so that upon power being applied to the motor (116) the socket drive (106) is rotated in relation to the body (102) . The direction of rotation may be electrically controlled by operation of a suitable switch (not shown) . Alternatively the direction of rotation may be changed by selection of appropriate direction controlling gears. The motor (116) may be hydraulic or pneumatic instead of electric. A housing of the motor (116) is fixed to the body (102) .

Referring to Figure 5, use of the device (100) is explained in more detail. A socket (126) is inserted over the socket drive (106) . The socket (126) is the typical type used with a socket wrench and has an internal hexagonally shaped hole (128) for receiving a nut (120) of

suitable size. The shaft (104) passes through the socket (126) and may be inserted in the hole (22) in the end (20) of a shank (14) of a bolt, such as that described above. It is noted that the bolt described above need not be used. It is merely necessary for the shank (14) of the bolt to have a suitably shaped hole in the end (20) thereof. The shank (14) and shaft (104) engage so that torque is transferred between them. In particular, if one is held stationary, the other will also be held stationary.

The nut (120) can then be screwed on to the thread (18) of the shank (14) of the bolt (14) by powering the motor (116) so as to rotate the socket drive (106) and thus the socket (126) , which in turn rotates the nut (120) relative to the shank (14) . The shank (14) is held stationary by its engagement with the shaft (104) which in turn is held stationary relative to the body (102) of the tool (100) . Thus any torque which is applied by the nut (120) to the shank (14) is in turn transferred to the shaft (104) and then in turn to the body (102) . Due to the housing of the motor (116) being fixed to the body (102) , any force produced by the torque transferred from the shaft (104) counteracts the force applied to the body (102) that is produced by operation of the motor (102) . If there is any resultant turning of the body (102) , this can be resisted by the user of the tool (100) . As the nut (120) is wound onto the shank (14) (to tighten the nut (210)), the end

(20) will move closer to the socket drive (106) . This is accommodated by the shaft (104) sliding through the socket drive (106) and braces (108) . When the tool (100) is removed, the shaft (104) will return to its starting

position under the motivation of the spring in the gap (110) .

Likewise, if the nut (120) is difficult to remove from the shank (14) , as is often the case when the nut (120) has seized, the tool (100) can be used by inserting the shaft (104) into the hole (22) and at the same time positioning the socket (106) over the nut (120) . This will typically involve pushing the tool (100) so as to move the shaft (104) further into the body (102) . Upon application of power to the motor (106) , the socket drive (106) will be rotated so as to rotate the socket (106) and thus the nut

(120) in a direction to loosen the nut (120) from the bolt

(14) . At the same time, particularly where a round bolt head is used (such as, for example, the bolt head of Figure 1) to prevent the shank (14) from rotating relative to the rest of the joint. Any torque applied by the nut (120) to the shank (14) is then in turn transferred to the shaft (104) which is then in turn transferred to the body (102) . Thus, the tool (100) can hold the bolt (14) still, preventing it from turning, while at the same time loosening the nut (120) so as to remove it from the bolt (14) .

An advantage of having the locking means in the fastener is that the problem of the shank winding through the bolt head is overcome .

An advantage of having the hole in locking means is that it is easier to tighten the locking means against the bolt shank.

An advantage of having the hole in the free end of the shank is that it is easier to tighten the bolt shank against the locking means.

Another advantage of having the hole in the free end of the shank is that the shank may be held while winding the nut on or off the shank from the same side of the joint. Thus there is no need to hold the bolt on both side of the joint, which is often inconvenient.

An advantage of the tightening/loosening tool is that a bolt with a hole in the free end of the shank can be easily held and at the same time the nut can be wound on or off the shank.

Modifications and variations may be made to present invention without departing from the basic inventive concept. Such modifications and variations may include the following. The hole in the locking means is not essential in some embodiments. Alternatively the hole may be in another form such as a slot(s) for receiving a Flat screwdriver or a hole for a Phillips, Star or other form of screwdriver. The hole in the end (20) of the shank need not be provided in the embodiment with the locking means . Alternatively it may be provided in an alternative form such as a slot(s) for receiving a Flat, Phillips, Star or other type of screwdriver. The bolt may have the hole in the end (20) of the shank but the locking means need not be provided in some embodiments .

The socket drive of the tool may be replaced with a socket of the most convenient size.

The drive mechanism of the tool could be rearranged such that the shaft is rotated relative to the body but the socket drive remains stationary relative to the body. Such an arrangement would be useful where it is desirable to hold a nut in place, but the shaft is to be rotated. This may be useful where a threaded stud is used instead of a bolt.

Such modifications and variations are intended to fall within the scope of the present invention, the nature of which to be determined from the foregoing description.